People have higher and higher requirements for the preservation of foods. Generally, in addition to freezing and refrigerating foods to inhibit bacterial growth, isolating air and moisture is also a way to avoid food deterioration. A conventional packaging bag is used for packaging dried foods. When the packaging bag is opened, there is no re-sealing structure. Another packaging bag is provided with a zipper for temporarily closing the mouth of the bag to prevent food from falling out or preventing cockroaches or other insects from entering the bag to contaminate the food. Because there is still a lot of air in the bag, the food (such as coffee, tea, etc.) in the bag may be deteriorated due to moisture.
Taiwan Utility Model Publication No. M564875, discloses a “Choke Valve for Packaging Bags”. A packaging bag is provided with a plurality of air outlets. A choke valve is attached to the inner side of the packaging bag, corresponding in position to the air outlets. The chamber of the choke valve is provided with a diaphragm that is confined by a plurality of stoppers for blocking a plurality of air holes on the bottom surface of the chamber. When the packaging bag is squeezed, the diaphragm is pushed up by the air from the air holes, and the air is exhausted through the air outlets. A pressure difference is formed inside and outside of the bag, so that the diaphragm is attached to the air holes to prevent outside air and moisture from entering the packaging bag. The above-mentioned conventional choke valve can exhaust the air in the bag to the outside by squeezing the bag and can prevent outside air from entering the bag to reduce the effect of air or moisture on the oxidative deterioration of the food.
By squeezing the packaging bag, most of the air in the packaging bag can be exhausted to the outside. However, a little air will be left in the bag. The little air still affects the deterioration or freshness of the food, and it is unable to ensure the safe shelf life of the food.
In view of this, the conventional dried food packaging bag needs to be improved, and its safety and convenience still need to be improved. Accordingly, the inventor of the present invention has devoted himself based on his many years of practical experiences to solve these problems and develop a dried food fresh-keeping packaging bag structure.